Diagnosis and actuator fault tolerant control in vehicle active suspension

This paper presents an application of a diagnosis and a fault tolerant control method for an active suspension system. This method detects and identifies an actuator fault and reconfigures the controller in order to maintain the ride comfort and vehicle performance in the presence of road disturbances. The proposed scheme consists of a diagnosis module and a controller reconfiguration module. The diagnosis module is based on the Unknown Input Observer approach to detect and identify actuator faults. A bank of observers is designed to generate residual signals such that each of them matches the system in a defined actuator fault mode. The controller reconfiguration module consists of a bank of controllers, each corresponding to a fault mode of the system. The module then changes the control law after the detection and the identification of an actuator fault. Simulation results show the effectiveness of the scheme applied to the active suspension system, which keeps its properties under the occurrence of severe faults.